Extended the expression methods to allow testing for existing scope by specifying a regex expression

We found this new functionality a requirement when restricting access to resources which could be managed by admin clients in their own namespaces:

"client1_admin:manage_scopes"
"client2_admin:manage_scopes" 
"client3_admin:manage_scopes" 
...

in this case we could use this expression: #oauth2.hasScopeMatching('.*_admin:manage_scopes')